Anatom3DPectoralis minor
Musculus pectoralis minor · Malý prsní sval
Muscles
Looks like
A thin triangle of muscle hidden under the large chest muscle, running from ribs 3 to 5 up to a bony hook at the front of the shoulder blade.
What it does
Pulls the shoulder blade forward and down, and lifts the ribs when breathing is hard.
Keeping it well
Long hours hunched forward shorten it and round the shoulders; stretching helps. The nerves and vessels to the arm pass beneath it, so pins and needles in the hand with the arm raised can come from here.